In recent years, various electronic devices such as notebook PCs (personal computers), tablet PCs, and smartphones have become widespread. Generally, the electronic devices of the above type comprise an interface function for transmitting and receiving data to and from external devices. As one of interface standards, the universal serial bus (USB) standard is known.
In the USB Type-C devices implemented according to the USB standard, a connector (a plug) of a cable can be inserted into a connector (a receptacle) of the electronic device in whichever orientation of regular (normal) and reverse (flipped). In other words, in a Type-C connector, a connection surface of the connector (arrangement of contact pins) has a shape of point symmetry, which is referred to as symmetry or a reversible configuration. More specifically, the connection surface has such a shape that the contact pins are arranged symmetrical with respect to a central point of the connection surface in a longitudinal direction.
When two electronic devices are connected via a cable conforming to the USB Type-C standard, these two electronic devices must each comprise a mechanism for enabling data transmission and reception without a problem in whichever orientation of normal and flipped the Type-C connector (plug) of the cable is inserted into the USB Type-C connector (receptacle) of the corresponding device. More specifically, the electronic device must be equipped with a switch that switches allocation of signal lines to the contact pins of the Type-C connector (receptacle). Accordingly, in order to enable an extension unit, which is referred to as a dock, for example, to be connected to a body apparatus by a cable conforming to the USB Type-C standard, the aforementioned switch must also be incorporated in the extension unit. In other words, the demerits were caused in terms of the cost and layout.
Meanwhile, if the extension unit is structured in such a way that a USB Type-C connector (receptacle) is not provided, and a cable is connected directly and fixedly, mounting the aforementioned switch is not required. However, the convenience and safety may be impaired.